The inferior temporal cortex is important for the visual processing underlying pattern recognition, and single neurons in this area are responsive to visual patterns. We are studying two aspects of these neuronal responses: one is the role of different stimulus features, and the other is the behavioral context in which the stimulus is presented. The presence of visual stimuli other than the probe stimulus markedly reduces neuronal responses to the probe, revealing an interaction within the visual system. Selective attention to the location or intensity of a probe stimulus will also reduce neuronal responses to it while selective attention to the pattern itself leads to increased neuronal response to the same stimulus. Using powerful new techniques developed for this project, we have found that different 2-dimensional pattern features are encoded in different aspects of the time sequence of neuronal discharge both in inferior temporal cortex and primary visual (striate) cortex. The spatial features encoded in different aspects of the neuronal discharge can be reconstructed.